Under these assumptions in the first step of the optimal two step design (Simon 1989) 21 patients have to be treated. As patients included during phase I are included in the efficacy analysis, this means an additional 10 patients to be treated. If less than three patients were successfully treated defined as an improvement in the remission status, the study will be stopped, because the success rate is unacceptably low. If three or more of the 21 patients are successfully treated, another 29 patients will be included. At the end of the study the success rate will be evaluated. If 8 or more of the 50 patients were successfully treated the therapy will be acceptable for further studies.